Wait list not working?

For a lot of raids, when I click "Wait list", nothing happens. I don't get an error message or anything of the sort as to why I can't queue for the raid, but the raid doesn't turn green to show I've queued. Literally just nothing happens.

I'm thinking the problem is me, I'm not understanding part of the addon and how it works etc, but I'm just not following.

Anyone know if it is me or if I'm experiencing a problem?